New COVID-19 study finds significant link between vitamin D and virus death rate
Researchers have found something unexpected: low virus mortality rates for those afflicted with COVID-19 is likely linked to high levels of vitamin D, based on data from at least 20 European countries. In our bodies, vitamin D modulates the action of white blood cells, preventing them from releasing too many inflammatory cytokines. Previous studies have shown that people with low levels of vitamin D are susceptible to acute respiratory tract infections caused by an excess of these inflammatory cytokines; just like the “cytokine storm” caused by the COVID-19 virus, for example.
The new data highlights high COVID-19 mortality rates in southern European countries such as Italy and Spain. Both countries have lower-than-average vitamin D levels than most northern European countries – its people, particularly the elderly, avoid strong sun, while skin pigmentation also reduces natural vitamin D synthesis.
In contrast, Scandinavian nations are among the countries in northern Europe with the lowest number of COVID-19 cases and mortality rates per head of population. This coincides with high average levels of vitamin D,possibly due to less sun avoidance and consumption of cod liver oil and vitamin D supplements.
“Vitamin D has been shown to protect against acute respiratory infections; and older adults, the group most deficient in vitamin D, are also the ones most seriously affected by COVID-19,” said Dr. Lee Smith at Anglia Ruskin University in Cambridge, England, who led the study.
“We suggest it would be advisable to perform dedicated studies looking at vitamin D levels in COVID-19 patients with different degrees of disease severity.”
However, “correlation does not necessarily mean causation,” said Petre Cristian Ilie, an Urologist at Queen Elizabeth Hospital King’s Lynn NHS Foundation Trust, also in England. “This study does have limitations because the number of cases in each country is affected by the number of tests performed, as well as the different measures taken by each country to prevent the spread of infection.”
